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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ProfilerCodeAddressService.h"
#include "platform.h"
#include "mozilla/StackWalk.h"
using namespace mozilla;
#if defined(XP_LINUX) || defined(XP_FREEBSD)
static char* SearchSymbolTable(SymbolTable& aTable, uint32_t aOffset) {
size_t index;
bool exact =
BinarySearch(aTable.mAddrs, 0, aTable.mAddrs.Length(), aOffset, &index);
if (index == 0 && !exact) {
// Our offset is before the first symbol in the table; no result.
return nullptr;
}
// Extract the (mangled) symbol name out of the string table.
auto strings = reinterpret_cast<char*>(aTable.mBuffer.Elements());
nsCString symbol;
symbol.Append(strings + aTable.mIndex[index - 1],
aTable.mIndex[index] - aTable.mIndex[index - 1]);
// First try demangling as a Rust identifier.
char demangled[1024];
if (!profiler_demangle_rust(symbol.get(), demangled, std::size(demangled))) {
// Then as a C++ identifier.
DemangleSymbol(symbol.get(), demangled, std::size(demangled));
}
demangled[std::size(demangled) - 1] = '\0';
// Use the mangled name if we didn't successfully demangle.
return strdup(demangled[0] != '\0' ? demangled : symbol.get());
}
#endif
bool ProfilerCodeAddressService::GetFunction(const void* aPc,
nsACString& aResult) {
Entry& entry = GetEntry(aPc);
#if defined(XP_LINUX) || defined(XP_FREEBSD)
// On Linux, most symbols will not be found by the MozDescribeCodeAddress call
// that GetEntry does. So we read the symbol table directly from the ELF
// image.
// SymbolTable currently assumes library offsets will not be larger than
// 4 GiB.
if (entry.mLOffset <= 0xFFFFFFFF && !entry.mFunction) {
auto p = mSymbolTables.lookupForAdd(entry.mLibrary);
if (!p) {
if (!mSymbolTables.add(p, entry.mLibrary, SymbolTable())) {
MOZ_CRASH("ProfilerCodeAddressService OOM");
}
profiler_get_symbol_table(entry.mLibrary, nullptr, &p->value());
}
entry.mFunction =
SearchSymbolTable(p->value(), static_cast<uint32_t>(entry.mLOffset));
}
#endif
if (!entry.mFunction || entry.mFunction[0] == '\0') {
return false;
}
aResult = nsDependentCString(entry.mFunction);
return true;
}
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